//input a number and output the trangle
#include<stdio.h>
int main(){
    int num=0;
    scanf("%d",&num);
    int i,j;
    int mid_index=num/2;
    int line_size=1;
    for(i=0;i<num;i++){
        for(j=0;j<line_size;j++){
            printf(". ");
        }
        printf("\n");
        if(i<mid_index){
            line_size++;
        }
        else{
            line_size--;
        }
    }

    return 0;
}